A diesel boat pulled into a foreign port, and put down maximum liberty.

  The skeleton crew didn't notice that a chimpanzee, escaped from a nearby
  civilian transport, had swung across the mooring lines onto the main
  deck.
  The After Engine Room hatch was open, so down the ladder it went.

  It came across a power panel opened up for maintenance. It couldn't read
  the warning signs, and with a bright blue blast, shorted out the ship's
  electrical system, and plunged the boat into darkness.

  A little bit later, the Below Decks Watch and a Torpedoman wandered
  through
  with their flashlights, looking for the problem.

  They came upon the blackened body of the chimp.

  They shined their flashlights on its long, burnt arms.

  They looked at each other.

  They highlighted its short legs and odd feet.

  They looked at each other again.

  Finally, one of them said, "Well, it's too hairy to be an yeoman, the
  legs are too short for a Ship's Cook, and there would be more
  tattoos on an Electrician. Call the Wardroom, and see if the Duty Officer is  missing."